Ade Lukmanul Hakimmm/ShutterstockWales has an ambitious goal: to achieve one million Welsh speakers by 2050. Schools are central to this. For many children, particularly those who do not speak Welsh at home, school is where they learn the language. But learning Welsh at school is not the same as continuing to use it after leaving. A learner acquires the language, but a speaker has the opportunities and confidence to use it beyond the classroom.My research explores what happens when young people finish compulsory education at age 16. The evidence points to a recurring problem. Many young people appear to use Welsh less often, feel less confident speaking it, or stop identifying as Welsh speakers altogether once they leave school.Yet, we still know little about how these changes happen, who experiences them, or why.Welsh is taught across Wales, but pupils’ experiences differ greatly. In Welsh-medium schools, Welsh is the main language of teaching. In dual-stream schools, Welsh and English-medium streams work alongside one another. In English-medium schools, Welsh is taught as a subject. What happens to young people’s Welsh after they leave compulsory education? Uniteam/Shutterstock These routes do not produce the same outcomes. Welsh-medium education can give pupils strong language skills and opportunities to use Welsh. Pupils in English-medium settings may have less contact with the language and fewer chances to speak it.Even strong skills at school do not guarantee continued use. At 16, the structures that supported Welsh use can disappear. A young person may enter an English-dominated college, university, apprenticeship or workplace. Their friendship groups may change. They may move away from a Welsh-speaking area. English may become the easier or expected choice.The evidenceFor my study, I reviewed census figures, surveys, qualitative studies and policy reports. Together, these suggested a consistent pattern but also serious limits in what we know.The censuses of 2001, 2011, and 2021, all recorded a lower percentage of Welsh speakers among 16 to 19-year-olds than among children aged 5 to 15. This might suggest a decline around the end of compulsory education.But census figures cannot prove that. They compare different age groups rather than following the same people over time. Parents often answer for children under 16, while older teenagers answer for themselves. The census asks whether someone can speak Welsh, but not how often they use it, how confident they feel, or how strongly they identify as a Welsh speaker.Research with young people suggests that reduced opportunities, lower confidence and the dominance of English in education or employment may contribute to less frequent Welsh use.These are clues, but they only tell part of the story. They point to different reasons, without showing which matters most or how young people are affected. Wales has set itself the goal of achieving 1 million Welsh speakers by 2050. Leighton Collins/Shutterstock From learners to speakersThis creates a problem for Welsh language policy. Wales often measures progress by counting how many people say they can speak Welsh. But ability, confidence and use are not the same thing.A young person may have learned Welsh at school but rarely use it afterwards. They may still understand the language, but feel uncomfortable using it with others. They may value Welsh while still seeing little place for it in their studies, work, or social life.Such a person has not necessarily lost their Welsh. Their relationship with the language may have changed because circumstances have changed.This problem is recognised at the highest levels of Welsh language policy. The Welsh language commissioner has identified the need to help young people retain their Welsh-language skills as they move into adulthood. Anna Brychan MS, the new cabinet minister for education and the Welsh language, has similarly warned that too many young people lose touch with Welsh after leaving school.But recognising this problem is not the same as understanding it. This is not just a gap in research. It is a major problem for Welsh language policy. Without knowing what happens after young people leave school, policymakers cannot tell whether learning Welsh leads to using it in adult life. Existing statistics cannot tell us when young people’s relationship with Welsh changes, why this happens, or which interventions would help. Success therefore cannot be measured only by how many pupils leave school able to speak Welsh. The next step is to follow young people more closely. Experts need to understand why some continue using Welsh, why others do not and what kinds of support make a lasting difference.The one-million-speaker target cannot be achieved through schools alone. Its success will also depend on whether young people have meaningful reasons, opportunities and confidence to use Welsh throughout their lives.Daniel Patrick Strogen does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.